Analyze the common faults of the gas control valve of the W4-60C excavator

In the dynamic gas circuit system of the W4-60C excavator, a gas control valve is installed between the air pump and the air storage tank. Its main function is to separate oil and water from the compressed air, filter red dust and impurities in the compressed air, prevent the compressed air in the air storage tank from flowing back to the air pump, and ensure that the gas pressure remains stable within the range of 0.490-0.637MPa. The maximum pressure does not exceed 0.784MPa. The following faults often occur during use:

The pressure regulating valve is leaking air due to the damage of the pressure regulating diaphragm

The pressure regulating diaphragm 6 is a rubber product. Due to its frequent repeated compression by air pressure, repeated arching and resetting actions, and corrosion by gas and moisture, the diaphragm is often damaged. This is the most common fault of this control valve. After the diaphragm is damaged, the compressed gas from the air pump enters the upper part of the pressure regulating valve through the diaphragm instead of entering the air storage cylinder, resulting in the air pressure in the air storage cylinder not being able to rise. At this time, the temperature of the pressure regulating valve is prone to rise, and the brake system pressure gauge indicates insufficient air pressure. A leakage sound can be heard at the pressure regulating valve.

2. The control valve housing is cracked

The valve housing is composed of three parts: upper, middle and lower, which are respectively connected by screws. As the shell is made of aluminium, when it is disassembled or reassembled, if the method of removing and installing screws is improper, the shell is prone to cracking. When disassembling or installing screws, they should be tightened or loosened diagonally and in multiple steps to ensure that the force on the mating surface of the shell remains consistent, preventing damage due to uneven force.